Folic Acid May Slow Age-Related Hearing Loss

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Folic Acid May Slow Age-Related Hearing Loss

January 3, 2007 10:55:31 AM PST

By Reinberg

HealthDay Reporter

http://health./news/170477;_ylt=AlfVYYPTmZQ6qcIR6yVP49CmxbAB

WEDNESDAY, Jan. 3 (HealthDay News) -- Age-related hearing loss, a common problem

among the elderly, might be related to inadequate levels of folic acid, European

researchers report.

The researchers found that people who took a folic acid supplement had less

decline in hearing low-frequency sounds over time, compared with people who

didn't take the supplement.

Results of the study, led by Jane Durga, of the Cognitive Sciences Group,

Nutrition & Health Department at the Nestle Research Center in Lausanne,

Switzerland, are published in the Jan. 2 issue of the ls of Internal

Medicine.

The researchers randomly assigned 728 older Dutch men and women, who showed

signs of age-related hearing loss and low folate levels, to receive either 800

grams of a folic acid supplement or a placebo daily for three years.

Durga's team chose to conduct the study in the Netherlands because, unlike the

United States, the Netherlands does not fortify its food with folic acid, a B

vitamin also known as folate. Folate levels in study participants were about

half those found in Americans. In the United States, many foods contain

supplemental folic acid because of its benefits in protecting against birth

defects.

At the end of the trial, the researchers found that the ability to hear

low-frequency sound did not decrease significantly among those taking folic acid

supplements. However, there was no slowing in the decline in hearing high

frequencies in either group.

The thresholds of the low frequencies increased by 1.0 decibel in the folic acid

group and by 1.7 decibels in the placebo group, the researchers said.

" Folic acid supplementation slowed the decline in hearing of the speech

frequencies associated with aging in a population from a country without folic

acid fortification of food, " the researchers wrote. " The effect requires

confirmation, especially in populations from countries with folic acid

fortification programs. "

But W. Sweetow, director of audiology at the University of California,

San Francisco, Medical Center, called the results " clinically insignificant. "

" I think that their conclusion that folic acid is actually slowing down the

progression of age-related hearing loss is a stretch, " Sweetow said. " I would

hate to say to patients, 'You take folic acid and the progression of your

hearing loss is going to slow down.' "

Another expert questioned the significance of the finding.

" The effect is on low frequency hearing, but most older folks have a problem

with high frequency hearing, " said Dr. Hinrich Staecker, an associate professor

in the department of otolaryngology-head & neck surgery at the University of

Kansas Medical Center.

Staecker also noted that the study authors didn't look at the ability of the

participants to hear speech clearly. " It's easier to make stuff louder, but it's

not easy to make stuff clearer, " he said.

Dr. M. Rabinowitz, an associate professor of medicine at the Yale

University School of Medicine, said, " The investigators' finding that

low-frequency, but not high frequency, hearing loss was reduced in the folate

supplementation group is somewhat surprising, since age-related hearing loss

usually affects the higher frequencies of hearing first and to a greater

degree. "

Clearly, much is not known about nutrition and hearing, Rabinowitz said. For

example, other studies have suggested that genetic differences in the metabolism

of folate may affect how someone responds to supplementation, including the

effect of folate on hearing loss, he said.

" While neither this study nor the current state of medical knowledge provide

adequate evidence for recommending particular supplements to prevent hearing

loss, this study provides additional evidence of the importance of adequate

nutrition in older adults, as well as the potential for future discoveries of

how to slow the aging process of the hearing system, " Rabinowitz said.

More information

The U.S. Food and Drug Administration can tell you more about age-related

hearing loss.